Fix overlong blocking in np_client_free()

When using ideviceinstaller, np_client_free() would block for several
minutes when ideviceinstaller cleans up after installing the
application.

This happens because the function is blocking on thread_join(), waiting
for the notification watcher thread to finish. It only ends when
np_get_notification() returns a negative value after getting a timeout,
which takes several minutes.

However, the thread loop will also exit early if client->parent gets
NULL (the loop is iterated every 500ms), so this commit ensures
client->parent gets set to NULL early in np_client_free() so that
thread_join() does not block for a long time.

Signed-off-by: Martin Szulecki <m.szulecki@libimobiledevice.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/src/notification_proxy.c b/src/notification_proxy.c
index dba42db..4b028f6 100644
--- a/src/notification_proxy.c
+++ b/src/notification_proxy.c
@@ -114,6 +114,7 @@ LIBIMOBILEDEVICE_API np_error_t np_client_start_service(idevice_t device, np_cli
 LIBIMOBILEDEVICE_API np_error_t np_client_free(np_client_t client)
 {
         plist_t dict;
+        property_list_service_client_t parent;
 
         if (!client)
                 return NP_E_INVALID_ARG;
@@ -123,12 +124,16 @@ LIBIMOBILEDEVICE_API np_error_t np_client_free(np_client_t client)
         property_list_service_send_xml_plist(client->parent, dict);
         plist_free(dict);
 
+        parent = client->parent;
+        /* notifies the client->notifier thread that it should terminate */
+        client->parent = NULL;
+
         if (client->notifier) {
                 debug_info("joining np callback");
                 thread_join(client->notifier);
         } else {
                 dict = NULL;
-                property_list_service_receive_plist(client->parent, &dict);
+                property_list_service_receive_plist(parent, &dict);
                 if (dict) {
 #ifndef STRIP_DEBUG_CODE
                         char *cmd_value = NULL;
@@ -150,8 +155,7 @@ LIBIMOBILEDEVICE_API np_error_t np_client_free(np_client_t client)
                 }
         }
 
-        property_list_service_client_free(client->parent);
-        client->parent = NULL;
+        property_list_service_client_free(parent);
 
         mutex_destroy(&client->mutex);
         free(client);